window.addEventListener('DOMContentLoaded',function(){
let end=document.querySelector('.conlusion').firstElementChild;
console.log(end);
let sessionKeys = Object.keys(sessionStorage)
    for (let i=0;i<sessionKeys.length;i++) {
        //可以对key 进行分析从而决定是否要删除sessionStorage 里的缓存
        console.log(sessionStorage.getItem(sessionKeys[i]))
    end.innerHTML+=sessionStorage.getItem(sessionKeys[i])+'</br>';
}
})